Rope-knife



H. w. McELHATTAN.

HOPE KNIFE. APPLICATION FILED MAY 2|. I919.

Patented Feb. 15,1921.

unites stares FATENT @FHQE.

ROEE-KNIFE.

Specification of Letters Patent.

Patented Feb. 15, 1921.

Application filed May 21, 1919. Serial No. 298,730.

To all whom it may concern:

Be it known that I, HARRISON XV. McEn- HATTAN, citizen of the United States of America, residing at Shippensville, in the county of Clarion and State of Pennsylvania, have invented new and useful Improvements in Rope-Knives, of which the following is a specification.

The object of the invention is to provide a device of relatively simple and eflioient con struction which can be used for the cutting and detachment of the operating rope from drill tools which have become jammed or wedged in a drill hole or well and which must therefore be abandoned, to the end that substantially the full length of the rope may be salvaged, and with this object in view the invention consists in a construction and combination of parts hereinafter described, it being understood that changes in form and proportion may be resorted to within the scope of the claims without departing from the principles involved.

Figure 1 is a side view of a'rope knife constructed in accordance with the invention.

Fig. 2 is a sectional view of the same.

Fig. 3 is a transverse sectional view on the plane indicated by the line 33 of Fig. 2.

Fig. 4: is a sectional view on the plane indicated by the line M of Fig. 2.

Fig. 5 is a detail view in perspective of the blade detached.

The device consists essentially of a tubular casing 10, having a head 11 consisting of a plug securely fastened at the upper end thereof to; support a jar bolt 12 which is mounted for reciprocatory movement in the guide opening 13 of the head, said bolt being provided with an enlarged lower terminal 14 for contact with the under surface of the head when it is necessary to jar the casing in the operation of the device, and being provided at its upper end with a polygonal wrench seat 15 and a threaded stud 16 for attachment to the tube or coupling of any suitable operating means (not shown). A longitudinal side opening or slot 17 may be provided in the side of the casing.

At its lower end the casing is provided with a stop or bearing finger 18 for contact with the tools to limit the lowering movement of'the device, and within the bore of the casing is arranged a blade 19 which is capable of movement longitudinally of the casing and also pivotally with reference to a support 20 which in the construction illustrated consistsof a longitudinal extending loop or keeper. In contour the knife corresponds approximately with the bore of the casing except that at its free edge it is provided with the V-notch 21 for cutting engagement with the rope which extending upward through the open lower end of the casing passes out through an opening 22 in the side wall thereof. The construction and mounting of this lmife are such that as the casing is lowered the knife will fold upward and pass freely over the surface of the rope or cable, whereas when an upward strain is applied to the casing by the elevating means connected with the jar bolt 12, the knife will fold downward to receive the rope in the cutting V 21 and thus sever the same.

As a means of limiting the downward swinging movement of the knife there is provided within the casing and below the plane of the knife, a seat 23 consisting of the upper tapered edge of a ring 24: secured tothe wall of the casing, for example, by rivets 25.

From the above description it will be seen that in operation it is necessary simply to lower the device until it has reached the point at which a severance of the rope or cable is desired whereupon a sufficiently vigorous upward strain upon the same, due to the gravitating action of the knife will result in the severance of the rope to permit of the withdrawal of the detached portion.

Claimed:

A rope knife having a tubular casing for the reception of a rope to be severed, a knife pivotally mounted within the casing for en gagement with the portion of a rope extending therethrough, and an axially movable jar bolt fitted in the upper end of the casing and having means for attachment to operating devices.

In testimony whereof I affix my signature.

HARRISON W. MQELHATTAN. 

